Various devices rely in whole or in part on portable power supplies such as one or more batteries. In many cases such portable power supplies are rechargeable; that is, within some reasonable bounds of operational integrity a given portable power supply can be recharged to equal or nearly equal a previously level of charge.
One prior art approach uses a single recharging process to recharge a portable power supply regardless of how fully the portable power supply may have been discharged. For example, some recharging processes rely upon a so-called constant-current, constant-voltage two-phase methodology that utilizes identical operational parameters essentially regardless of how fully or partially the portable power supply might actually be discharged.
A significant relationship is known to exist, however, between depth of discharge for a portable power supply on the one hand and total life cycle on the other hand. Such a monolithic approach as is presented above essentially ignores this relationship and offers a single charging solution that usually fails to permit any dynamic adjustment that might offer improved life cycle performance.
One prior art approach seeks to redress this situation by using different charge voltages and/or different current cut-off values during battery recharging. For example, a battery can be repeatedly charged using a first charge voltage during a first time period and then repeatedly charged using a second charge voltage during a second time period. By establishing a difference between the first and second charge voltage, at least under some operating circumstances one can expect to utilize the second charge voltage to diminish the battery's capacity at a different (hopefully better) rate than when using the first charge voltage.
Such an approach, while offering possible advantages under some operating circumstances, nevertheless fails in other respects to meet the needs of certain users. For example, using this approach, the battery will often be only partially charged following the charging process. So long as the user does not require full capacity performance this accommodation may be acceptable. When, however, the user needs the full capacity of the battery for whatever reason, this approach poorly serves the user's needs.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.